There is currently about a $2 per box savings in 12 ga reloads vs retail target loads ( using #8's or whatever ) .......but there is potentially a much bigger savings in using OO buck, depending on where you get your shot from. I have not loaded a significant volume of OO buck, except in some .410 to play around with at my local range. But there is some savings....plus you can customize the shell to whateve specs you want in terms of velocity and ounces of shot...
All of my shotshell presses are progressive - and so is my metallic....so every time I pull the handle, a finished shell or cartridge comes off the back.
One isn't really easier than the other...once the press is setup ...its setup.
Volume is about the same ...on both presses / my metallic is a 5 station press...my shotshell presses are 6 station presses - but getting 800 rds an hour off any decent progressive press is pretty easy if its auto indexing ( like a MEC 9000 GN or MEC 9000 HN for shotshells / or a Dillon 650 for metallic.